Selective addition of thiols to allylic isocyanates and isothiocyanates

ABSTRACT

THIOLS CAN BE ADDED TO THE OLEFINIC BOND OF ALLYL ISOCYANATES AND ISOTHIOCYANATES TO FORM THE CORRESPONDING ANTI-MARKOVNIKOV TYPE ADDUCTS. THE RESULTING PRODUCTS ARE USEFUL AS PESTICIDES, ESPECIALLY AS POST-EMERGENCE HERBICIDES, AND AS POLYMER INTERMEDIATES.

United States Patent 01 3,597,341 Patented Aug. 3, 1911 ABSTRACT OF THEDISCLOSURE Thiols can be added to the olefinic bond of allyl isocyanatesand isothiocyanates to form the corresponding anti-Markovnikov typeadducts. The resulting products are useful as pesticides, especially aspost-emergence herbicides, and as polymer intermediates.

PRIOR ART It is known that isocyanates and isothiocyanates react withthiols under ionic conditions, especially at elevated temperatures, toyield thiourethanes, H. L. Snape, Ber. vol. 18, pages 24-32 (1885); E.Dyer and J. F. Glenn, J. Am. Chem. Soc., vol. 79, p. 366 (1957).

Such formation of thiourethanes is accelerated by ionic catalysts andheating.

However, the prior art has not been cognizant of the selective lowtemperature reaction of the olefinic group of unsaturated isocyanatesand/or isothiocyanates with thiols under free radical conditions to formnovel, useful anti-Markovnikov type adducts.

FIELD OF THE INVENTION This invention relates to novel thiol adducts ofallylic isocyanates and isothiocyanates, formulations or compositionsthereof, and process or methods for preparing and using same. Moreparticularly, this invention relates to the selective free radicaladdition of thiols to the olefinic double bond of allylic isocyanatesand isothiocyanates to form anti-Markovnikov type adducts having utilityas pesticides, particularly as post-emergence herbicides and as polymerintermediates, particularly polyurethane intermediates.

SUMMARY OF THE INVENTION The novel anti-Markovnikov adducts of thisinvention are generally prepared in the course of a free radicaladdition process wherein a variety of thiols can be added to theolefinic double bond of a variety of allylic isocyanates andisothiocyanates. In general, this reaction may be illustrated with allylisocyanate and isothiocyanate in accordance with Equtaion 1 below.

EQUATION 1 RSH CH2=CHCH2N=C=X RS-CH2-CI-I2-CHrN=C=X RSCH(OH3)CH2N=C=X III wherein X is O or S, product I is formed in major amounts, andproduct II is formed in minor amounts, R being C C hydrocarbyl moietysuch as C to C alkyl, C to C monosubstituted alkyl, C to C disubstitutedalkyl, C to C aryl, C to C monosubstituted aryl, C to C disubstittuedaryl. The aliphatic moiety has preferably C to C carbon atoms. Thearomatic moiety is preferably phenyl. Preferable substituents arechlorine, bromine, C C alkylthio, hydroxy, C -C alkyloxy, C -Calkylsulfonyl, phenylsulfonyl, cyano, C -C carboalkoxy alkyl, acetyl,nitro, etc. substituents, which catalyze the reaction of the thiolgroups with the isocyanate or isothiocyanate groups must be absent. Suchsubstituents are all strongly basic and acidic groups such asalkylamino, sulfonic acid, phosphonic acid, etc.

In like manner, substituted allylic isocyanates and isothiocyanates canbe reacted with thiols in accordance with the following equation,Equation 2.

wherein X is O or S, product I is again the major product, and productII the minor product, R to R being such moieties as hydrogen, CH Cl, CN,and C 'C alkylthio substituted methyl, phenylthio substituted methyl, CC monosubstituted phenylthio substituted mehyl, ec.

Typical, non-limiing thiol reactants include such thiols asmethanethiol, propanethiol, hydroxyethanethiol, alphatoluenethiol,benzenethiol, xylenethiol, chlorobenzenethiol, t-butanethiol,3-chloropropanethiol, hexadecanethiol, naphthalenethiol,phenanthrenethiol, anthracenethiol, trichlorobenzenethiol,bromobenzenethiol, 3-hydroxypropanethiol, carbomethoxyethanethiol,Z-methylthioethanethiol, nitrobenzenethiol, methanesulfonylbenzenethiol,cyclohexanethiol, Z-acetylethanethiol, 12-hydroxydodecanethiol,18-carboethoxyoctadecanethiol, 5,6- dichlorohexanethiol, Z-butenethiol,2,3-epoxypropanethiol, etc.

Typical, non-limiting isocyanate and isothiocyanate reactants of thisinvention include crotyl isocyanate, 2- methallyl isocyanate,4-methylthiocrotyl isothiocyanate, 4-phenylthiocrotyl isocyanate,4-chlorophenylthiocrotyl isocyanate, 4-nitrophenylthiocrotyl isocyanate,2-chl0roallyl isothiocyanate, Xylylthiocrotyl isocyanate.

When a dithiol is reacted with an allyl isocyanate or isothiocyanate oneor both thiol groups may participate in the addition reaction to theallylic double bond, as is shown in Equation 3 below.

EQUATION 3 wherein R is a divalent organic radical such as C O alkylene,C C phenylene, C -C phenalkylene, e.g. xylylene. The alkylene group canalso contain hetero atoms such as S, S0 0, Si(CH groups in which themaximum carbon number of the continuous alkylene unit is twenty, thenumber of alkylene-heteroatomic group units (n) being 0 to 100, e.g.:

Typical, non-limiting dithiol rectants include 1,3- propanedithiol, 1,6hexanedithiol, cyclooctanedithiol, cyclododecanetrithiol,1,2-ethanedithiol, benzenedithiol, Xylylene dithiol, 2-thio bisethanethiol, 2-sulfonyl-bisethanethiol, 3-oxy-bis-propanethiol,3-hydroxy-1,2-propanedithio], 3-chloro-1,2-propanedithiol,polyethylenethioetherdithiol, polyethyleneoxidedithiol,polyethylenesulfonedithiol, polypropylenethioetherdithiol, etc.

The monoadduct intermediate of the dithiol-allyl isocyanate intermediaecan undergo a polyself-addition initiated by heat and/or ionic catalyststo form a polythiourethane, as shown in Equation 4 below.

wherein n is 1 to 500, preferably 20 to 200.

Alternatively, the diadduct may be reacted with a diol or dithiol toyield a polyurethane, as shown in Equation 5.

In the case of trithiol reactants, the selective additions to allylisocyanate and isothiocyanate can be carried out to various degrees, asshown in Equation 6.

EQUATION 6 wherein (1) R" is a trivalent unsubstituted organic radicalcontaining from 6 to 500 carbon atoms, which radical can be substitutedby such atoms as sulfur, oxygen and silicon, illustrative examples ofthese substituted radicals including polythioether, polyether, andpolysilane trithiols, etc.; and (2) X is O and S, preferably 0.

Typical, non-limiting trithiol reactants include tri mercaptoethylcyclohexane, tri-mercaptoethylthio cyclododecane, the tri-mercaptoaceticacid ester of tri-hydroxymethyl methane, the tetra-mercaptopropionicacid ester of pentaerythritol, polypropylenethioether trithiol, thedi-mercaptoacetic ester of pentaerythritol, the polythiol resulting frompolybutadiene excess hydrogen sulfide addition, the hexathiol resultingfrom trivinyl cyclohexane-hydrogen sulfide addition, the trithiolresulting from polypropylenethioether-dithiol-trivinyl cyclohexaneaddition, etc.

In the case of polythiols the number of allyl isocyanate moleculesreacted per molecule of polythiol can equal up to the number of thiolgroups in the polythiol. The general reaction is shown by Equation 7.

wherein (l) R' is a polyvalent organic radical containing from 6 to 200carbon atoms, which radical can be substituted by such atoms as sulfur,oxygen and silicon, illustrative examples of these substituted radicalsincluding polythioether, polyether, and polysilane polythiols, etc.; (2)p and q are 3 to 30, with q being equal to or smaller than p; and (3) Xis O or S, preferably 0.

Preferreddithiols are polymethylene and polymethylenethioether dithiolseach of which can be reacted with allyl isocyanate in accordance withEquation 8.

EQUATION s A preferred trithiol is the triaddtion product of thereaction of polymethylene and polymethylenethioether 4 dithiols withtrivinyl cyclohexane, which reaction is shown in Equation 9.

EQUATION 9 When allylic isocyanates or isothiocyanates of this inventionare reacted with polythiols, it is to be understood that the resultingreaction can be either a partial one or can be run until completion.

Without wishing or intending to be bound by any theory, it isnevertheless believed, from the structure of the adducts obtained, thatthe selective additions of this invention take place by means of a freeradical type chain mechanism and in accordance with the followingpostulated reaction mechanism.

Initiation initiator Propagation p 1 RS-CH CH--CH -NCO Step (2 REACTIONCONDITIONS The reaction temperatures employed in this invention arepreferably kept below 0, most preferably below about 50 C., in order toavoid concurrent ionic reactions of the isocyanate group which result inthe formation of by-products. The lower limit of the reactiontemperature range is defined by the freezing point of the reactionmixture employed, reaction initiation, and the cost of refrigeration.Reaction temperatures are between about and about +100 C., preferablybetween about 80 and about +50 C. For the initiation of the lowtemperature, selective free radical reactions, nonchemical initiatorsare preferred, such as ultraviolet light, gamma radiation, etc. However,chemical initiators can also be used below the temperature limits of thereactions. For example, chemical initiators such as peroxides, derivedfrom boron alkyls are suitable low temperature initiators. Otherchemical initiators include azo compounds, such asbis-azo-i-butyronitrile, etc.

Usually the reactions of this invention are carried out with equivalentamounts of reactants in the liquid phase at atmospheric pressures. Ifthe thiol reactant is gaseous at the reaction temperature,superatmospheric pressure can be used to keep it in the liquid state.Alternatively, such a thiol as, e.g., ethanethiol, can be slowlyintroduced into the radiated, liquid allylic isocyanate compound. Ingeneral, the isocyanate reactants are good solvents for the thiols.Solid thiols can essentially be dissolved in the isocyanate reactants toobtain liquid reaction mixtures. However, the use of nonreactivesolvents at times can be desirable. Exemplary of suitable solvents arethe openchain and cyclic hydrocarbons such as heptane, cyclohexane,benzene, xylene, etc.; aliphatic sulfides such as dimethyl sulfide;dialkyl ethers such as diethyl ether; esters such as ethyl acetate;dialkyl sulfones such as diethyl sulfone; etc.

Although the reactants are usually employed in equivalent amounts, anexcess of either reactant beyond the stoichiometric requirements can beused with beneficial results. For example, an excess of methanethiol canbe used to increase the rate of the overall addition reaction to allylisocyanates. Upon completion of the free radical addition, the excessthiol can be remove or used for anionic addition to the isocyanate groupto form the corresponding thiourethane in accordance with the followingequation, Equation 10.

E Q UATION 10 (1) omen CH NCO CHQS (CHm excess The dithiol reactants ofthis invention such as e.g., ethane dithiol, can be reacted with half ofthe stoichiometric requirements of allyl isocyanate to yield a thiolisocyanate product which is itself subject to polyauto-addition tothereby result in a polyurethane product in accordance with thefollowing equaltion, Equation 11.

wherein R, R R and X are as previously defined in Equation 2.

The preferred monothiol adducts of this invention have the formulaIllustrative nonlimiting examples of R include methyl,

'octadecyl, t-butyl, phenyl, naphthyl, anthryl, cyclohexyl,

3-chloropropyl, trichlorophenyl, hydroxyethyl, nitronaphthyl,methanesulfonylphenyl, carboethoxymethyl, epoxypropyl, cyanoethyl,acetylphenyl, etc.

The preferred monothiol adducts include ethylthiopropyl isocyanate,ethylthiopropyl isothiocyanate, cyanoethylthiopropyl isothiocyanate,dichlorophenylthiopropyl isothiocyanate, hexadecylthiopropylisothiocyanate, naphthylthiopropyl isothiocyanate, etc.

In general, the dithiol adducts of this invention are characterized bythe following formulae:

not

and

X Polyadduct wherein R, X, and n are as previously defined in Equations3 and 4.

Illustrative, nonlirniting examples of R include propylene,trimethylene, ethylene, xylylene, phenylene, polyethylene thioether,polypropylenethioether, polyethyleneoxide, polyethylenedimethylsilane,polyethylene sulfone, polydodecamethylenethioether, etc.

In general, the trithiol adducts of this invention are characterized bythe following formula:

wherein R" is as previously defined in Equation 6.

The polythiol adducts of this nvention are generally de scribed by thefollowing formula:

wherein R', p, q, and X are as previously defined in Equation 7.

The anti-Markovnikov adducts of this invention are valuableintermediates which can themselves undergo all the customary reactionsundergone by isocyanates and isothiocyanates in general with suchtypical reactants as alcohols, thiols, acids, amines, oximes, water,etc. Moreover, the products derived from the reaction of dithiols, andpolythiols with allylic isocyanates are especally useful in polymerchemistry as monomers and cross-linking agents.

The diisocyanate, triisocyanate and polyisocyanate containing adducts ofdi-, triand polythiols are mainly utilized in polymer chemistry asmonomer components with diols, triols, polyols and diamines, triamines,polyamines, and water. Their reaction as monomer components leads topolyurethanes and polyureas. Difunctional diisocyanates when reactedwith diols and diamines yield linear polymers. Polyfunctonal isocyanatesare useful as crosslinking agents.

As previously noted, the anti-Markovnikov adducts of this invention arealso useful as pesticides, particularly as post-emergence herbicides.For pesticidal uses it is preferable that the adduct be derived from amono or dithiol. As the other component an allylic isothiocyanate ispreferred. It is furthermore preferred that the pesticidal adduct shouldhave a molecular weight of less than 500. The dithiol used in thepreparation of pesticides is preferably a C to C polymethylene dithiol.

When used as post-emergence herbicides, the biologically activeingredients are preferably formulated with a suitable carrier or diluentor combinations thereof.

The term carrier or diluent as used herein means a material, which canbe inorganic or organic and synthetic or of natural origin, with whichthe active ingredient of this invention can be mixed or formulated tofacilitate its storage, transportation and handling, and application tothe plants, e.g., weeds, to be treated. The carrier is preferablybiologically and chemically inert and, as used, can be a solid or afluid. When solid carriers are used, they are preferably particulate,granular, or pelleted; however, other shapes and sizes of solid carrierscan be employed as well. Such preferably solid carriers can be naturallyoccurring minerals-although subsequently subjected to grinding, sieving,purification, and/or other treatments, including for example, gypsum;tripolyte; diatomaceous earth; mineral silicates such as mica,vermiculite, talc, and pyrophyllite; clays of the montmorillonite,kaolinite, or attapulgite groups; calcium or magnesium limes; or calciteand dolomite; etc. Carriers produced synthetically, as for example,synthetic hydrous silica oxides and synthetic silicates can also beused, and many proprietary products of this type are availablecommercially. The carrier can also be an elemental substance such assulfur or carbon, preferably an activated carbon. If the carrierpossesses intrinsic catalytic activity such that it would decompose theactive ingredient, it is advantageous to incorporate a stabilizingagent, as for example, polyglycols such as diethylene glycol toneutralize this activity and thereby prevent possible decomposition ofthe active anti-Markovnikov ingredient.

For some purposes, a resinous or waxy carrier can be used, preferablyone which is solvent soluble or thermoplastic, including fusible.Examples of such carriers are natural or synthetic resins such ascoumarin, resin, rosin, copal, shellac, dammar, polyvinyl chloride,styrene polymers and copolymers, a solid grade of polychlorophenol suchas is available under the registered trademark Arochlor, a bitumen, anasphaltite, a wax, for example, beeswax, or a mineral wax such asparaffin wax or Montan wax, or a chlorinated mineral wax, or amicro-crystalline wax such as those available under the registeredtrademark Mikrovan wax. Compositions comprising said resinous or waxycarriers are preferably in granular or pelleted form.

Fluid carriers can be liquids, as for example, water, or an organicfluid, including a liquefied normally vaporous or gaseous material, andcan be solvents or nonsolvents for the active material. For example, thehorticultural petroleum spray oils boiling in the range of from about275 to about 575 F., or boiling in the range of from about 575 to about1000 F. and having an unsulfonatable residue of at least about 75% andpreferably of at least about 90%, or mixtures of these two types of oilsare particularly suitable liquid carriers.

The carrier can be mixed or formulated with the active material duringits manufacture or at any stage subsequently. The carrier can be mixedor formulated with the active material in any proportion depending uponthe nature of the carrier. One or more carriers, moreover, can be usedin combination.

The compositions of this invention can be concentrated, suitable forstorage and transport and contain, for example, from about to about 95%by weight of the active ingredient, preferably from about 20 to about 80Weight percent. These concentrates can be diluted with the same or adifferent carrier to a concentration suitable for application. Thecompositions of this invention can also be dilute compositions suitablefor application. In general, concentrations of about 0.1 to about byweight of the active material based on the total weight of thecomposition, are satisfactory, although lower and higher concentrationscan be applied if necessary.

The compositions of this invention can also be formulated as dusts.These comprise an admixture of the active ingredient and a finelypowdered solid carrier such as aforedescribed. The powdered carriers canbe oil-treated to improve adhesion to the surface to which they areapplied. These dusts can be concentrates, in which case a highlysorptive carrier is preferably used. These require dilution with thesame or a different finely powdered carrier, which can be of lowersorptive capacity to a concentration suitable for application.

The cofipositions of this invention can also be formulated as Wettablepowders comprising a major proportion of the active ingredient mixedwith a dispersant, i.e., a deflocculating or suspending agent, and, ifdesired, a finely divided solid carrier and/ or a wetting agent. Theactive ingredient can be in particulate form or adsorbed on the carrierand preferably constitutes at least about 10%, more preferably at leastabout 35% by weight of the final pesticidal composition. Theconcentration of the dispersing agent should in general be between about0.5 and about 5% by weight of the total composition, although larger orsmaller amounts can be used if desired.

The dispersing agent used in the composition of this invention can beany substance having definite dispersant, i.e., deflocculating orsuspending properties as distinct from wetting properties, althoughthese substances can also possess wetting properties as well.

The dispersant or dispersing agent used can be protective colloids suchas gelatin, glue, casein, gums, or a synthetic polymeric material suchas polyvinyl alcohol and methyl cellulose, etc. Preferably, however, thedispersants or dispersing agents used are sodium or calcium salts ofhigh molecular weight sulfonic acids, as for example, the sodium orcalcium salts of lignin derived from sulfite cellulose waste liquors.The calcium or sodium salts of condensed aryl sulfonic acids, forexample, the products known as Tamol 731, are also suitable.

The wetting agents used can be nonionic type surfactants, as forexample, the condensation products of fatty acids containing at least12, preferably 16 to 20, carbon atoms in the molecule, or abietic acidor naphthenic acid obtained in the refining of petroleum oil fractionswith alkylene oxides such as ethylene oxides or propylene oxides, orwith both ethylene oxides or propylene oxides, as, for example, thecondensation product of oleic acid and ethylene oxide containing about 6to 15 ethylene oxide units in the molecule. Other nonionic wettingagents like polyalkylene oxide polymers, commercially known as Pluronicscan be used. Partial esters of the above acids with polyhydric alcoholssuch as glycerol, polyglycerol, sorbitol, mannitol, etc., can also beused.

Suitable anionic wetting agents include the alkali metal salts,preferably sodium salts of sulfuric acid esters or sulfonic acidscontaining at least 10 carbon atoms in a molecule, for example, thesodium secondary alkyl sulfates, dialkyl sodium sulfosuccinatesavailable under the registered trademark Teepol, sodium salts orsulfonated castor oil, sodium dodecyl benzene sulfonate, etc.

Granulated or pelleted compositions comprising a suitable carrier havingthe active ingredient incorporated therein are also included in thisinvention. These can be prepared by impregnating a granular carrier witha solution of an active ingredient or by granulating a mixture of afinely divided carrier and the active ingredient. The carrier used cancontain a fertilizer or a fertilizer mixture, such as for example, asuper phosphate.

The compositions of this invention can also be formulated as solutionsof the active ingredient in an organic solvent or mixture of solvents,such as, for example, alcohols; ketones, especially acetones; ethers;hydrocarbons; etc.

Where the toxicant itself is a liquid these materials can be sprayedupon crops without further dilution.

Petroleum hydrocarbon fractions used as solvents should preferably havea flash point about 73 R, an example of this being a refined aromaticextract of kerosene. Auxiliary solvents such as alcohols, ketones, andpolyalkylene glycol ethers and esters can be used in conjunction withthese petroleum solvents.

Compositions of the present invention can also be formulated asemulsifiable concentrates which are concentrated solutions ordispersions of the active ingredient in an organic liquid, preferably awater-insoluble organic liquid containing an added emulsifying agent.These concentrates can also contain a proportion of Water, for example,by volume, based upon the total composition to facilitate the solutionwith water. Suitable organic liquids include, e.g., the above petroleumhydrocarbon fractions previously described.

The emulsifying agents can be of the type producing water-in-oil typeemulsions which are suitable for application by low volume spraying, oran emulsifier of the type producing oil-in-water emulsions. Oil-in-wateremulsions can be used, producing concentrates which can be diluted withrelatively large volumes of water for application by high volumespraying or relatively small volumes of water for low volume spraying.In such emulsions, the active ingredient is preferably in anon-aqueous-phase.

The present invention is further illustrated in further detail byfollowing examples, but it is to be understood that the presentinvention, in its broadest aspects, is not necessarily limited in termsof the reactants or specific temperatures, residence times, separationtechniques, and other process conditions, etc.; or dosage levels,exposure times, test plants used, etc., by which the compounds and/orformulations described and claimed are preferred and/ or used.

9 EXAMPLE 1 Ultraviolet light-initiated addition of methanethiol toallyl isocyanate CHsSH CH2=OHCH2NCO CHaS(CH2)aNCO (major product) CHQSOH(OH CHzNCO (minor product) Into a quartz pressure tube equipped with amagnetic stirrer and a Teflon screw valve, 49.8 grams (0.6 mole) ofallyl isocyanate was placed. Then, 38.4 grams (0.8 mole) ofmethane-thiol was condensed to it, using a Dry Ice bath. The tubecontaining the reaction mixture was placed into a water bath,thennostated at 15 C., and mounted upon a magnetic stirrer drive. Thestirred reaction mixture was then irradiated troma distance of 5centimeters by a 75 watt Hanan ultraviolet immersion lamp having a highpressure mercury arc emitting a wide spectrum radiation.

The reaction mixture was sampled during the irradiation to determine theprogress "of the addition. Nuclear magnetic resonance spectroscopy (NMR)was found to be a suitable, semi-quantitative tool for the analysis ofthe samples. It showed that 80% of the allyl isocyanate reacted in thefirst half-hour irradiation time. A total of three hours ultravioletirradiation resulted in more than 95% conversion of the isocyanate. NMtRalso showed that all the addition took place at the olefinic bond. Itcould also be determined by NMR that 90% of the addition took place inan anti-Markovnikov manner to yield 3-methylthiopropyl isocyanate. Aboutof the adduct was of the opposite orientation, i.e., 2-methylthiopropylisocyanate. The absence of ionic thiourethane adducts indicated thatboth adducts were formed by a selective, free radical mechanism.

Distillation of the reaction mixture in vacuo yielded 71.5 grams (91%)of the isomeric adduct mixture as a clear, colorless, mobile liquid,boiling at 33-35 C. at 0.2 mm. pressure. A fractional distillationresulted in an enrichment of the branched adduct isomer in the earlyfractions.

Elemental analysis-Calculated for C H NOS (percent): C, 45.78; H, 6.91;S, 24.44; N, 10.67. Found (percent): C, 45.52; H, 7.05; S, 24.38; N,10.66.

1 EXAMPLE 2 Gamma irradiation-initiated addition of methanethiol toallyl isothiocyanate CH SH CH2=CHCH2NCH CH S(CH2)3NCS (major product)CHQS CH(OH3) CH2NC S (minor product) A mixture of 69.3 grams (0.7 mole)of distilled allyl isothiocyanate and 32.4 grams (0.675 mole) ofmethanethiol was reacted in a Pyrex pressure tube under the effect ofgamma irradiation. The reaction was initiated from 10 cm. distance with4 Co plates emitting about 4500 curies. Five hours irradiation resultedin about 40% conversion of the methanethiol to yield the allylicadducts. About 90% of the isomeric adducts was 3-methylthiopropylisothiocyanate, while 10% Was the branched 2- methylthiopropylisothiocyanate.

The crude reaction product was distilled in vacuo to yield the isomericmixture as a clear, light yellow liquid boiling at 7678 C. at 0.6 mm.pressure.

Elemental analysis.-Calculated for the distillate, C H NS (percent): C,40.78; H, 6.16; 8, 43.55. Found (percent): C, 40.38; H, 6.34; and S,43.57.

-A reaction of equimolar amounts of reactants under the above conditionsresulted in 53% conversion in 16 hours. The isomeric adduct mixtureconsisted of about 91% 3-methylthiopropyl isothiocyanate and 9%2-methylthiopropyl isothiocyanate.

10 EXAMPLE 3 Ultraviolet light-initiated addition of methanethiol toallyl isothiocyanate CHQSH CHz=CHCH2NCS (31138 (CH2)3NOS (major product)CH3 S CH(CH3) CHzNC S (minor product) (minor product) A mixture of 69.3grams (0.7 mole) of distilled allyl isothiocyanate and 33.6 grams (0.7mole) of methanethiol was irradiated with two 75 watt Hanau immersionlamps for 127 hours at 16 C., resulting in 90% reaction of themethanethiol. An NMR spectrum of the crude reaction mixture indicatedthat of the adduct was 3-methylthiopropyl isothiocyanate. Eleven percentwas the branched adduct, 2-methylthiopropyl isothiocyanate. About of theadduct was N-allyl-S-methyldithiocarbamate, which resulted by theaddition of the thiol to the isothiocyanate group.

Distillation of the crude reaction product in vacuo yielded a mixture ofthe 3- and Z-methylthiopropyl isothiocyanate as a liquid distillateidentical with the product of the previous example.

EXAMPLE 4 Ultraviolet light-initiated addition of 2-propanethio1 toallyl isothiocyanate (CHmCH S (CHMNC 0 (major product) (CI-I3) 2CH SCH(OH CHQNC 0 (minor product) A mixture of 80.7 g. (0.97 mole) ofdistilled allyl isocyanate and 73.9 g. (0.97 mole) 2-propanethiol wasirradiated with two Hanan lamps as described in the previous example.NMR indicated that 5 hours of irradiation resulted in 79%, and 24 hoursof total irradiation in 93%, reaction of the allyl isocyanate. After theremoval of the unreacted volatile components of the mixture under 0.1mm. pressure, it could be estimated by NMR that the residue consisted of95% 3-i-propylthiopropyl isocyanate and 5% 2-i-propylthiopropylisocyanate.

Distillation of the crude residual product at 0.05 mm. pressure yieldedg. of the clear colorless liquid product boiling between 3436 C. Basedon the reacted amounts of starting materials this amount corresponds toan isolated yield of 97% for the isomeric mixture of olefinic adducts.

Elemental analysis.-Calculated for C7H13OSN (percent): C, 52.80; H,8.22; N, 8.79; S, 20.14. Found (percent): C, 52.52; H, 8.28; N, 8.93; S,19.81.

EXAMPLE 5 Ultraviolet light-initiated addition of Z-methyl-2-propanethio1 to allyl isocyanate A mixture of 84.2 g. (1.01 mole) ofdistilled allyl isocyanate and 89.3 g. (0.99) of Z-methyl-Z-propanethiolwas irradiated as described in the previous example. NMR spectroscopy ofsamples, taken at periodic intervals from the reaction mixture,indicated allyl isocyanate conversions of 64% after 4 hours and of 93%after 64 hours irradiation. After the removal of the volatile reactantsin vacuo, NMR analysis of the crude reaction product indicated that itwas mostly 3-t-butylthiopropyl isocyanate.

Distillation of the crude product at 0.05 mm. yielded 152 g. of theclear, colorless liquid boiling between 37- 39C. This represents a 95%yield based on the con- EXAMPLE 6 Ultraviolet light-initiated additionof benzenethiol to allyl isocyanate @sr-r CH2=CHCH2NCS Q-swmmvoo (majorproduct) (minor product) CH2= CHCH2NH-C S@ (minor adduct) A stirredmixture of 55 grams (0.5 mole) of benzenethiol and 43.6 grams (0.525mole) of allyl isocyanate was irradiated in a quartz reaction vesselwith a 75 watt Hanau immersion lamp at 15 C. Four hours irradiationresulted in about 50% conversion of the isocyanate as indicated by NMR.A total of 24 hours irradiation resulted in about 75% conversion to thetwo isomeric adducts resulting by addition to the olefinic bond. NMR ofthe reaction mixture also indicated that the relative percentages of theadducts were 93% 3-phenylthiopropyl isocyanate and 7% Z-phenylthiopropylisocyanate.

Fractional distillation of the mixture in vacuo yielded 55 grams (57.5%)of the isomeric adducts as .a clear, colorless, mobile liquid boiling at87--90 C. at 0.1 mm. It was observed during distillation that theheating caused some reaction of the thiol with the isocyanate group.

Elemental analysis.Calculated for C H ONS (percent): C, 62.15; H, 5.73;N, 7.25; S, 16.59. Found (percent): C, 62.28; H, 5.89; N, 7.19; and S,16.74.

EXAMPLE 7 Gamma irradiation-initiated addition of benzenethiol to allylisothiocyanate (olefinic product) (cyanate adduct) Q-swnnmnomQ(diadduct) decomposition of the by-products according to the followingreaction schemes:

The volatile decomposition products were removed by distillation. NMRindicated that the residual product g.) was mostly the olefinic adduct,i.e., 3-phenylthiopropyl isothiocyanate. Based on the amount of startingmaterials this corresponds to a yield of 35%.

Elemental analysis.Calculated for C H S N (percent); C, 57.38; H, 5.29;N, 6.69; S, 30.64. Found (percent): C, 57.l1; H, 5.46; N, 7.04; S,30.45.

EXAMPLE 8 Ultraviolet light-initiated addition of ethanedithiol to allylisocyanate HS(OH2)2SH 2CH2=CHCH2NCO O CN(CH2)3S(CH2)2S(CH2)3NC 0 (majorproduct) OCN(CH2)3S(CH2)2SOH(CH3) OHzNCO (minor product) A stirredmixture of 94 grams (1.0 mole) of ethanedithiol at 182.6 grams (2.2mole) of allyl isocyanate was irradiated in a quartz tube at 15 C. by aWatt Hanau ultraviolet immersion lamp. One hour irradiation resulted inthe conversion of 55% of the isocyanate. A total of 5 hours irradiationconverted about of the isocyanate. Removal of the excess allylisocyanate by distillation gave a quantitative yield of a crude,residual product having an NMR spectrum corresponding to that of amixture containing 92% of straight diadduct, ethylene-bis-3- thiopropylisocyanate, and 8% of the corresponding partially branched diadduct.

Distillation of the crude product in vacuo yielded 161.2 grams (62%) ofthe diadduct as a colorless, clear liquid, distilling at 147150 C. at0.2 mm. pressure. 'NMR indicated that the rest of the product, which wasa brown residue, also consisted mainly of the same diadduct.

Elemental analysis.Calculated for C H N O S (percent): C, 46.13; H,6.19; N, 10.76; and S, 24.63. Found (percent): C, 46.39; H, 6.32; N,10.62; and S, 24.56.

EXAMPLE 9 Ultraviolet light-initiated addition of ethanedithiol to allylisothiocyanate CH2=CHCHzNHCS2(CH2)2S2CNHCH2OH=CH3 (cyanate diadduct) Amixture of 29.7 g. (0.3 mole) of allyl isothiocyanate and 14.1 g. (0.15mole) of ethanedithiol was irradiated in the manner described in theprevious example. NMR showed that hours irradiation resulted in thereaction of 45% of the allylic double bonds to form the correspondingallylic adducts. About 22% of the thiocyanate groups also reacted toform the cyanate adducts.

EXAMPLE 10 Gamma irradiation-initiated addition of ethanedithiol toallyl isothiocyanate A mixture of 99 g. (1 mole) of allyl isothiocyanateand 47 g. (0.5 mole) of ethanedithiol was reacted with initiation from agamma ray source as described in Example 2. NMR indicated that 22 hoursradiation resulted in 32% reaction of the allylic group. Subsequentirradiation for 70 hours plus 8 days standing resulted in a finalreaction mixture, in which 57% of the allylic and 18% of the isocyanatedouble bonds were reacted.

An attempted distillation of the reaction mixture from a bath at 135 C.at 0.2 mm. pressure resulted in the decomposition of the dithiocarbamategroups formed by isothiocyanate addition. For example, the decompositionof the isothiocyanate diadduct can be indicated by the following scheme.

The volatile decomposition products were removed by distilaltion. An NMRspectrum of the residual product 120 g.) indicated that it was mostlythe olefinic diadduct, i.e. 3-(ethylene)-bis-thiopropyl isothiocyanate.Based on the amount of starting materials, the residual adduct wasobtained in a yield of 82%.

EXAMPLE 11 Ultraviolet light-initiated addition of ethyl mercaptoacetateto allyl isocyanate 0211.020 omen orr2=oHoH2No o CQHO2CCH2S(CH2)3NCO(major product) CH=CHCH2NHC 0 801120 OZCZH (minor product) A=mixture of83 g. (1 mole) of allyl isocyanate and 120 g. (1 mole) of ethylmercaptoacetate was irradiated by two ultraviolet lamps as described inExample 1. NMR analysis showed that most of the thiol reacted in anhour. About 75% thiol addition occurred to the allylic double bond. Tocomplete the reaction, the reaction mixture was irradiated for 14 morehours. The volatile components of the mixture were then removed at 0.05mm. As a residual product, 190 g. (93%) of crude adduct was obtained.NMR indicated that it contained 80% of the major product, i.e.3-carboethoxymethylthiopropyl isocyanate and about of the minor product,i.e. ethyl S-(N-allyl)-carbamoyl thiolacetate.

An attempted distillation of the crude adduct yielded some 3carboethoxymethylthiopropyl, isocyanate, as a clear colorless liquiddistilling at 97 C. under 0.5 mm. pressure With decomposition.

Elemental analysis.Calculated for C H NO S (percent): C, 47.28; H, 6.44;N, 6.89; S, 15.77. Found (percent): C, 47.05; H, 6.46; N, 6.75; S,15.63.

EXAMPLE 12 CH2CH2S OH CH SH 2 (Diadduct) (allylic monoadduct) (diadduct)A solution of 41.5 g. (0.5 mole) of allyl isocyanate and 72.25 g. (0.5mole) of p-chlorobenzenethiol in ml. dimethyl sulfide Was irradiatedwith an ultraviolet lamp in the manner described in Example 1. NMRindicated that in 48 hours 32% of the allylic double bonds reacted withthe thiol to form the allylic monoadduct, i.e.3-p-chlorophenylthiopropyl isocyan ate. No other products could beobserved.

An attempt to fractionally distill the reaction mixture at 0.1 mm. froma 160 C. bath resulted in the formation of the diadduct as a residualproduct.

EXAMPLE 13 Gamma irradiation-initiated addition of polythioether dithiolto allyl isocyanate A magnetically stirred mixture of 20 g. (0.24 mole)of allyl isocyanate and g. (0.1 mole) of polythioether (PTE) dithiol ofthe above formula was irradiate with gamma rays for 16 hours in themanner described in Example 3. The crude reaction product was thenheated at C. for 2 hours under 005 mm. to remove the excess allylisocyanate. A study of the NMR spectrum of the residual productindicated that a complete and selective addition of the PTE dithiol toform the allylic diadduct took place. A number average molecular weightdetermination of the product in benzene solution by a vapor pressureosmometer gave a value of 1268. The calculated molecular weight of thediadduct is 1266.

Elemental analysis-Calculated for C47H94N2O2S14 (diadduct of 1168molecular weight) (percent): C, 48.33; H, 8.12; N, 2.39; S, 38.43. Found(percent): C, 48.13; H, 8.02; N, 2.40; S, 38.90.

EXAMPLE l4 Ultraviolet light-catalyzed addition of allyl isocyanate topolythioether tetrathiol CHgS CI'I CH (CH CH S CH2CH2SI1 21 4CH=OHCH NCOMolecular weight calculated: 795.5. Found: 897.

Number of SH Groups per molecule calculated: 4.0. Found: 4.4.

(Tetrathiol) CH SCHzCH CHzCHz C 2 5 (Crosslinked PolythioetherThiourethane) A magnetically stirred mixture of 32.12 g. (0.39 mole) ofallyl isocyanate and 80.7 g. (0.09 mole) of liquid polythioether (PTE)tetrathiol, derived from the addition of ethanedithiol to 1,2,4-trivinylcyclohexane, was irradiated with an ultraviolet lamp in thet mannerdescribed in Example 3. The progress of the allylic addition reactionwas followed by NMR spectroscopy. In 28 hours, 69% of the allylisocyanate reacted. A liquid product mixture consisting of a majoramount of triadduct and a minor amounts of diadduct was formed. Theunreacted allyl isocyanate was removed from this mixture at 0.2 mm. atroom temperature. Subsequent heating of the liquid residual product at135 C. for two hours resulted in crosslinking. This is due to athermally induced ionic reaction of the thiol .groups with theisocyanate groups to form thiourethane bonds. The crosslinked product isa very tough, hard polymer insoluble in benzene.

HOCHZOHZS CHZ=CHOHZNCO HO OH CH MOHZMNC O (allylic monoadduct) HOCHZCH SCHmNHC CH, CH S (polythioethe r polyurethane polyadduct) A mixture of91.3 g. (1.1 mole) of allyl isocyanate and 78 g. (1 mole) ofhydroxyethanethiol was irradiated with an ultraviolet lamp in the mannerdescribed in Example 1 for 100 minutes. NMR spectroscopy indicated thatallylic monoaddition took place with a reactant conversion of 95%. Theunreacted volatile components of the mixture were removed underdiffusion pump vacuum at 1.5 X- mm. The resulting residual product is3fl-hydroxyethylthiopropyl isocyanate, a clear, colorless, mobileliquid. During 72 hours standing at room temperature, it was convertedinto a linear polythioether polythiourethane of 7589 number averagemolecular weight by self-polyaddition.

Elemental analysis.-Calculated for C H NOS (percent): C, 49.63; H, 7.63;N, 9.64; S, 22.08. Found (percent): C, 49.75; H, 7.48; N, 8.78; S,21.68.

EXAMPLE 16 Ionic addition of thiolacetic acid to allyl isocyanateCHaCOSH CH2=CHOHZNCO CH2=CHOH2NHC 0S 0 O CH (eyanate adduct) To 43.6 g.(0.525 mole) of stirred allyl isocyanate 38 .g. (0.5 mole) ofthiolacetic acid was added dropwise below 33 C. in minutes. Anexothermic reaction started immediately with the addition of the acid,which required ice-Water cooling during the addition. The excess allylisocyanate was subsequently removed at 0.25 mm. overnight. The NMRspectrum of the liquid, residual product showed that a quantitativeyield of the ionic adduct derived by addition to the isocyanate groupwas obtained.

EXAMPLE 17 Ultraviolet light-catalyzed addition of n-dodecanethiol toallyl isocyanate A mixture of 16.6 g. (0.2 mole) of allyl isocyanate and40.4 g. (0.2 mole) of n-dodecanethiol is irradiated by an ultravioletlamp in the manner described in Example 1 for 24 hours. An NMR spectrumof the resulting reaction product shows that it is mostly the straightchain olefinic adduct, i.e. 3-n-dodecylthiopropyl isocyanate.

1 6 EXAMPLE 18 EXAMPLE 19 Ultraviolet light-catalyzed addition ofxylenethiol to 2-methally1 isocyanate (EH3 CH cm-Qs-crn-orr-omqvo 0 Amixture of 27.6 g. (0.2 mole) of xylenethiol and 16.6 g. (0.2 mole) of2-methallyl isocyanate is irradiated as described in Example 1 for 24hours. An examination of the reaction mixture by NMR shows that themethallylic adduct, i.e. 3-xylylthiopropyl isocyanate, is formed.

EXAMPLE 20 Azo-bis-isobutyronitrile catalyzed addition of methanethiolto allyl isothiocyanate A magnetically stirred mixture of 29.7 g. (0.3mole) of allyl isothiocyanate, 15.4 g. (0.31 mole) of methanethiol and3.3 g. (0.02 mole) of azo-bis-isobutyronitrile was heated for 24 hoursat 40 C. A subsequent examination of the reaction mixture showed that afree radical addition to form 3-methylthiopropyl isocyanate occurredwith 30% conversion. In 96 hours the conversion was 70%.

EXAMPLE 21 Thiol-allylic isocyanate and isothiocyanate adducts aspost-emergence herbicides A number of the adducts from those prepared inthe previous examples were evaluated for post-emergence herbicidalactivity in this example. The test procedure employed was as follows:

Appropriate crop plant and weed species were seeded by growth-timerequirement schedules in individual disposable four-inch squarecontainers, watered as required, and maintained under greenhouseconditions. When all crop plants and weeds had reached suitable growthdevelopment, generally first true leaf stage, plants and weedsappropirate to pertaining test requirements were selected for uniformityof growth and development. One four-inch container of each plant andweed, averaging six (Corn) to fifty (Crabgrass) or more plants or weedsper individual container, was then placed on carrying tray fortreatment. Generally, six crop and six weed containers were used in eachevaluation.

Candidate compounds were dissolved in acetone and, as appropriate,diluted in water containing wetting and emulsifying agents. Althoughisocyanates can react with water the results were not significantlyinfluenced when, instead of the acetone solutions, aqueous emulsionswere used for spraying the containers.

The application rate was ten pounds per acre and, as controls, allylisocyanate and 2,4-dichlorophenoxy acetic acid were used at the 10- and2-pounds per acre rate, respectively. The results are given in Table I,and show that the adducts of this invention are effective postemergenceherbicides. While not wishing or intending to be bound by any theory, itis, nevertheless, believed that, for acceptable biological activity, thepresence of both the thioether and the isocyanate groups is necessary;allyl Overall response Crab- Buck- Morning Crop Weed grass wheat gloryindex index Physiological responSe of plants Injury to weeds Barn- SoyYellow yard beans Cotton Mustard foxtail grass Injury to crops Sugarbeets Corn Oats Clover TABLE I.POST-EMERGENCE HERBICIDAL ACTIVITY OFISOCYANATES AND ISOTHIOCYANATES Rate, Chemical structure lbs/acre win06:15

cor-i 14:5

on: P1

coo P1 com =Severe injury; plants usually did p growth. 4-6

S CH2OH2CH2NCO CHZS CHzCHzCHzNCO] -0 CHzC O Na =Caustic. D=Dlstorted.

Slight injury; plant usually recovered with little or no reduction in toisocyanate shows little activity. It is to be further noted that theisothiocyanate adduct of methanethiol is more ac tive than thecorresponding isocyanate adduct and that the aromatic thioetherisocyanates seem to be preferable to the corresponding aliphaticthioethers.

EXAMPLE 22 Pesticidal spectrum of 3-methylthiopropyl isothiocyanate3-methylthiopropyl isothiocyanate, the product of Example 2, wasexamined in various standard pesticidal screening tests for itspesticidal activity.

An aqueous emulsion containing 0.05% of the active chemical was found tokill, as a systemic poison, pea aphids.

When applied as an acetone solution at a rate of 100 lbs. activematerial per 4 inch deep acre, the chemical completely controlled theroot knot nematode on tomatoes.

When tested as a foliar fungicide on 6-8 inch high Wheat plants, anacetone solution containing 0.5% of the chemical completely protectedthe plants against the cereal leaf rust, Puccinia recondita.

As a soil fungicide, the chemical was active against Rhizoctonia fromcotton and Fusarium from tomato. For a positive effect, the compound wasapplied as an acetone solution at a rate of 36 lbs. per acre activematerial to the soil.

It should be understood from the foregoing that the above description ismerely illustrative of the preferred embodiments and specific examplesof the present invention and that in all of which embodiments andexamples, variations, such as, e.g., those previously described, can bemade by those skilled in the art without departing from the spirit andpurview thereof, the invention being defined by the following claims.

What is claimed is:

l. A process for the preparation of thiol adducts of allylic isocyanatesand isothiocyanates, which comprises reacting a thiol with an olefiniccompound selected from the group consisting of allylic isocyanates andallylic isothiocyanates under free radical conditions.

2. A process for the preparation of thiol adducts of allylic isocyanatesand allylic isothiocyanates, comprising reacting, under free radicalconditions, a thiol with an olefinic compound having the general formula11.12 m Ill where R to R are selected from the group consisting ofhydrogen, methyl, chlorine, cyano, C to C alkylthio substituted methyl,phenylthio substituted methyl, C to C mono-substituted phenylthiosubstituted methyl, and combinations thereof, and X is selected from thegroup consisting of oxygen and sulfur.

3. A process for the preparation of thiol adducts of allylic isocyanatesand allylic isothiocyanates, comprising reacting, under free radicalconditions, an olefinic com- 1e Numb er Exam 1 CH3S CHZOHZCHZNC S 2 CH3SCHZCHZCHZNCO 6 Control- CH2=CHCHzNCO pound selected from the groupconsisting of allylic iso- 1| 9: cyanates and allylic isothiocyanateswith a thiol of the gen- 25 eral formula RSH, where R is selected fromthe group gg consisting of C to C alkyl, C to C mono-substituted g6.alkyl, C to C aryl, C to C mono-substituted aryl, and 25 C to Cdisubstituted aryl. fig 7 4 A process for the preparation of thioladducts of allylic isocyanates and allylic isothiocyanates, comprisingf? reacting, under free radical conditions, a thiol having the 3%general formula RSH, where R is selected from the group +2 consisting ofC to C alkyl, C to C monosubstituted alkyl, C to C aryl, C to Cmonosubstituted aryl, and

C to C disubstituted aryl with an olefinic compound having the generalformula R1 R3 R4 C=OON=C=X I i; l, where R to R are selected from thegroup consisting of hydrogen, methyl, chlorine, cyano, C to C alkylthiosubstituted methyl, phenylthio substituted methyl, C to Cmonosubstituted phenylthio substituted methyl, and combinations thereof,and X is selected from the group consisting of oxygen and sufur.

5. A process according to claim 4 wherein the reaction is conducted at atemperature of between about l C. and about C. in the presence of a freeradical catalyst.

6. A process according to claim 5 wherein said reaction is carried outin a liquid phase.

7. A process for the preparation of dithio adducts of an allyliccompound selected from the group consisting of allyl isocyanate andallyl isothiocyanate, comprising reacting, in the liquid phase, aboutone mole of dithiol of the formula wherein R is a divalent C to Corganic radical selected from the group consisting of C to C alkylene, Cto C phenylene, and C to C phenalkylene in which said alkylene radicalcan be interrupted by 0 to 50 heteroatomic groups, said reaction beingeffected at a temperature of less than about +l00 C. and in the presenceof a free radical catalyst.

8. A process for the preparation of trithiol adducts of an allyliccompound selected from the group consisting of allyl isocyanate andallyl isothiocyanate, comprising reacting, in the liquid phase, aboutone mole of a trithiol with at least about one mole of said allyliccompound, said trithiol having the formula wherein R" is a trivalentorganic radical selected from the group consisting of unsubstituted C toC trivalent organic radicals and substituted C to C trivalent organicradicals, the nonhydrocarbon substituents of said substituted radicalsbeing selected from the group consisting of sulfur, oxygen and silicon,said reaction being effected at a temperature of between about and +100C. in the presence of a free radical catalyst.

9. A process for the preparation of polythiol adducts of an allyliccompound selected from the group consisting of allyl isocyanate andallyl isothiocyanate, comprising reacting, in the liquid phase, at atemperature of between about 150 and about +100 C. in the presence of afree radical catalyst at least about one mole of said allylic compoundwith about one mole of a polythiol having the general formula ReferencesCited UNITED STATES PATENTS 9/1956 Seeger et a1. 260-453 4/1969Farrissey et a1. 204l58 HOWARD S. WILLIAMS, Primary Examiner US. Cl.X.R. 260-453, 454

